I was required to switch to Levothyroxine, after 15 years on synt...

I was required to switch to Levothyroxine, after 15 years on synthroid,because my insurance co. would no longer cover synthroid. I started Levothyroxine Oct 1/04 and within about 2 weeks my knee, elbows, arms, hands, legs, ankles and feet started to ache constantly. The knee was so bad for 6 weeks, that I couldn't walk - it felt like a broken, achy bone. Sometimes the pain feels like a burn. The muscles feel weak too. The pain moves around. This all seemed to happen suddenly. I also can't sleep well and feel very tired through the day. I had blood tests, MRI, xrays, etc which showed no rheumatoid arthritis, only very mild cartilage wear in the sore knee. Nothing so far has explained the pain in the muscles. I have very good health in every area, low sugar, low cholesterol, good weight, take lots of vitamins, etc. I don't drink, and I avoid any drugs, even pain killers. I eat a healthy diet, mostly organic and no artificial sweeteners, lots of fresh and raw veggies, no fatty meat, etc. Levothyroxine is the only change in my lifestyle recenly that I can think of. I think I should ask my doctor to switch me back to synthroid. Has anyone tried Armour thyroid and do you like it and why?